.tooltip {
    position:relative;
    display: inline-block;
}
.tooltip .tooltiptext {
    visibility:hidden;
    opacity:0;
    transition:opacity 1s;
    background-color:#092525;
    color:#fff;
    font-size: 24px;
    width:140px;
    text-align:center;
    padding:5px 0;
    border-radius:6px;
    z-index:1;
    position:absolute;
    top:110%;
    left:50%;
    margin-left:-70px;
    /* 使用一半宽度 (140/2 = 70) 来居中提示工具 */
}
.tooltip .tooltiptext::after {
    content:" ";
    position:absolute;
    bottom:100%;
    left:50%;
    margin-left:-5px;
    border-width:5px;
    border-style:solid;
    border-color:transparent transparent #092525 transparent;
}
.tooltip:hover .tooltiptext {
    visibility:visible;
    opacity:1;
}